Federal parliament is voting under a critical misconception on a key element of the Murray Darling Basin Plan, according to National Irrigators chief executive Steve Whan.

On May 8 the Senate will vote on a disallowance motion brought by the Greens, which will require support from Labor and some of the Crossbench.

They will vote on the approval of a suite of 37 infrastructure projects designed to simultaneously improve the flow of water to environmental assets like wetlands, and reduce by 605 gigalitres the amount water buybacks required of irrigators.

The Greens want to prevent parliament granting the necessary approval to the project proposals, which they said would shortchange the environmental benefit of the Basin Plan water recovery process.

But in his submission to the Productivity Commission’s five-year review of the Basin Plan, Mr Whan said the Basin Plan laws are a safety net that prevent the projects’ performance becoming a risk to the environment.

The MDBA have already signed off on project designs, but they must assess actual water delivery in six year’s time. If they’re not up to scratch, the shortfall must be recovered through buybacks from irrigators.

“The critical point is that the 605GL assessment attached to these projects is subject to a full reconciliation in 2024,” Mr Whan said.

“If the projects fail to deliver their projected outcomes, the gap is met by acquiring water from irrigators.”

On the other side of the debate are irrigators, the federal government and the MDBA, who say the offset projects will deliver equivalent environmental benefits by reducing evaporation, moving water more efficiently and increasing the capacity of the river system to deliver the large flow targets required for South Australia, without unwanted flooding along the way.

The offset project disallowance motion follows the Greens successful disallowance motion in February, which blocked the Northern Basin amendment, recommended by the Murray Darling Basin Authority, which would have reduced recovery in the region by 70GL, from 390GL to 320GL.

Both the offset projects and the Northern Basin amendment were written into the Basin Plan in its conception on 2012.

Irrigators and farm groups generally want the Basin Plan to continue.

Mr Whan is campaigning to prevent the Senate from blocking the offset projects, and urged all parties to adhere to the Basin Plan’s principle of adaptive management.

National Irrigators Council cheif executive Steve Whan.

“It is absolutely true that some of the projects require much more work. They are in their early stages. The planning, consultation and implementation is still to happen,” he said.

“The National Irrigators Council would encourage communities, scientists, environmentalists and irrigators to actively engage in the planning process to ensure that these projects do deliver the environmental benefits anticipated.”

Backgrounder: what are the offset project?

What that means is upgrades to infrastructure or river operations to move water more efficiently.

Moving water more efficiently sends more of it to where it's needed and less being lost in evaporation.

The MDBA has calculated that the 37 offset projects proposed by NSW, Qld, Vic. and SA can reduce the recovery target of 2750GL by 605GL.

Offset projects include new works to increase the effectiveness of wetland inundation with with environment water such as the construction of levees, regulators and a pipeline at Victoria’s Belsar-Yungera Floodplain, reconfiguring weirs in Gunbower forest and re-engineering Menindee Lakes to reduce evaporation.

The efficiencies gained by through these projects enable irrigation cutbacks to be reduced (there’s more detail here on the MDBA website) https://www.mdba.gov.au/basin-plan-roll-out/proposed-adjustment-sustainable-diversion-limits

Here’s how the numbers work: the Basin Plan requires irrigation be cut to meet the Sustainable Diversion Limit of 10,873GL a year (the overall flow into the Basin’s waterways each year, on average, is 32,500GL by the way).

The Sustainable Diversion Limit is another way of saying “the volume of water which the Murray Darling Basin Authority (MDBA) says is the amount that can be taken while maintaining a healthy river system”.

That’s the point of Basin Plan, which was brought in because the Millenium Drought highlighted the unhealthy over-allocation of the Basin’s water.

So the MDBA did the calculations and determined that irrigation should be reduced by 2750GL (this figure is the recovery target I told you about before).

The bulk of the 2750GL, around 2100GL or so, has already been recovered through direct buybacks, or co-investments between the Commonwealth and farmers to swap water entitlements for on-farm upgrades.

That means the 605GL slated to come through offset projects can deliver the rest of the water reduction - without the need for further irrigation cuts.

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